Is squashed loft insulation less efficient?

pinksleepybear

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My loft insulation rises about 15cm above the height of the floor joists. I'd like to put some flooring down, just so that I can use the loft for storage.

Can I just squash the insulation down by that much underneath the flooring, or would it be much less efficient?

???

Gaz_Hammer

Hi,
It will certainly reduce the efficiency of the insulation because it works on the principle of hollow fibre (traps air like quilts etc.) but by how much the efficiency will be reduced - ??? Don't Know!

Generally one would install extra timbers/battens on the existing joists to bring it up to the top of, or as near damn it, the lagging and then fit flooring on these timbers.

Hope this helps
Gaz

trafalgar_2

My loft insulation rises about 15cm above the height of the floor joists.  I'd like to put some flooring down, just so that I can use the loft for storage.  

Can I just squash the insulation down by that much underneath the flooring, or would it be much less efficient?

???

If you have a depth of 8 inches to your joists and the insulation rises above that , it is fine to put boards down, we did ;D

The recommended thickness is 8 inches

Gaz_Hammer

Hi,
sorry to pick at straws -

The recommended thickness is 8 inches

The actual thickness requirement of the current Part L Building Regs is 250mm (10inches).

Gaz

trafalgar_2

My apologies search the lazy way
"Check that the depth of loft insulation is at least 200mm/8ins and upgrade if necessary. "

from here
http://www.redcar-cleveland.gov.uk/Living1.nsf/0/6d5a901e94bbb06480256d67003b556f?OpenDocument&Click=

but should of double checked ......................10 it is

cattie

I recently had new loft insulation prior to having the loft completely boarded. I was advised to go for an insulation by the name of Airtec double. It's thin, foil backed & equivalent to 55mm of polystyrene insulation.

It wasn't cheap, but saved me having to have battens on the joists to enable the required airflow, which of course I would have to have paid the guy to do anyway, so I think was cost effective on that point. It was quick, easy & clean for the guy to lay. He was able to lay it over the existing insulation, which was far from adequate anyway.

mini

Be careful when you squash your insulation, we used boards across joists for storage & found the pressure on the ceiling below was too much & cracked it in a few places :-/ oops, Wish I'd asked Gaz!

Haggis_n_Neeps

Be careful when you squash your insulation, we used boards across joists for storage & found the pressure on the ceiling below was too much & cracked it in a few places  :-/ oops, Wish I'd asked Gaz!

Yup, I've seen many, many houses where the owner/occupiers have changed their loft to storage.

Many roof structures (especially modern ones) are not designed to take storage loading, resulting in massive deflection of the ceiling below, cracking and in 2 cases that I've been involved in actual collapse of the roof. Check with your local Council's Building Regs section for more info re converting your loft (even adding flooring can in some cases require consent !!)

The performance of glass wool loft insulation is reduced (as stated by an earlier poster) as it works on the principle of little air pockets, and by squashing them you are reducing the number of and volume of the air pockets (now, if only some 'builders' could understand this ::) )

Patti

Just read all the advice on loft insulation, I have just boarded my loft floor for storage, didn't realise about the depth so kept the insulation the same depth as the joists. The quality of the insulation differed quite considerably, I think the builder must have used any he had left over from other jobs. Is there anything I can do now that doesn't mean taking up the boards. ???